Haldane's Rule

Haldane's Rule states that when two different species breed, the hybrid offspring are often less viable or fertile if one of the parent species is a "rarer" species. Essentially, if a hybrid’s parents are from two different species, and one species is much less common, the hybrid is more likely to encounter problems such as being less healthy or unable to reproduce. This rule highlights how the differences in genetics and populations can affect the success of hybrids, providing insight into evolutionary biology and species conservation.